The present invention relates to improvements in work supporting devices in general, and more particularly to improvements in devices which render it possible to change the orientation of a workpiece by rotating or pivoting the workpiece about a plurality of mutually inclined axes. Work supporting devices of the type to which the present invention pertains can be used in private workshops as well as in smaller, medium-sized or large manufacturing, assembling or repair plants of all kinds.
It is already known to mount the base of a work supporting device on a bench or on a like support, to mount on the base a chuck carrier in such a way that the latter can pivot about two mutually inclined axes, to mount the chuck on or in the carrier, and to provide means for locking the chuck in a selected position so as to allow for proper treatment of (e.g., removal of material from) a workpiece which is held in the chuck, either directly or by means of a suitable work holder. By way of example, work supporting devices of the just outlined character can be used for treatment (including polishing) of electrodes or other types of workpieces which require secondary treatment, e.g., by hand. Such secondary treatment is unavoidable in connection with a wide variety of mass-produced (e.g., machined) workpieces because a secondary treatment in automatic or semiautomatic machines is too expensive or not possible. Some of the treatments to which numerous mass-produced workpieces must be subjected include polishing, truing, removal of burrs or other sharp projections, ultrasonic treatment and many others. Some of these secondary treatments must be carried out while the workpiece which is held in the chuck of the work supporting device is observed by way of a magnifying glass, a microscope or other suitable optical enlarging means. A prerequisite for adequate manual treatment is proper mounting of the workpiece in a supporting device and reliable retention of the workpiece in a selected position so that the workpiece is held in an optimum orientation and/or at an optimum level for observation and manual treatment.
In accordance with a presently known proposal, the connection between the chuck carrier and the base of a work supporting device comprises a universal (spherical) joint and means for releasably locking the joint. If the locking means is actuated to release the joint, the latter allows for movements of the chuck and of the workpiece in the chuck to any one of a practically infinite number of different positions. A drawback of the just discussed work supporting device is that the universal joint does not allow for rapid and highly accurate selection of the desired position (level and/or orientation) of the workpieces, such as the aforediscussed electrodes. One of the reasons is that the operator cannot readily avoid simultaneous angular displacements of the chuck carrier about more than a single axis, e.g., only about a vertical axis or only about a horizontal axis. In other words, a universal joint is not suited to allow for rapid and/or accurate selective angular displacement of the clamped workpiece about a single axis or for selective angular displacement of the workpiece about several axes in a predetermined sequence.